On this site you will find

iPhone/iPad/iPod touch Apps

Information- and help page for various iPhone/iPad/iPod touch apps such as BetterBrain, iDungeon, iAltairHD and EarPlayer.

Download on the App Store

AltairZ80 Simulator

Download pages for the AltairZ80 simulator which works on Windows, Macintosh, Linux and Zaurus. Also there is rich collection of operating systems including CP/M, programming languages such as Basic, C, Pascal, and application programs (e.g. WordStar and MultiPlan) ready to run on the simulator.

XYZ GeoBench

Download the XYZ GeoBench for Macintosh including Object Pascal source code. The GeoBench is an interactive system featuring algorithm animation for geometric computation.

Other Interests

You can find pictures and information about our travels on Verena's home page. If you are interested in Swiss German (Schweizerdeutsch) have a look at www.schweizerdeutsch.info.

Prime Proof

Proof of Peter Schorn: Assume there exist only m prime numbers.

Let n = m + 1. For two numbers i and j with 1 ≤ i < jn, then

gcd[ (n!)i + 1, (n!)j + 1 ] = 1.

Indeed, j = i + d, with 1 ≤ d < n, so

gcd[ (n!)i + 1, (n!)j + 1 ] = gcd[ (n!)i + 1, (n!)d ] = 1.

Therefore the n integers (n!)i + 1 (for i = 1, 2, …, n) are pairwise relatively prime. If pi is a prime dividing (n!)i + 1, then p1, p2, …, pn are distinct primes with n = m + 1, which is a contradiction [Paulo Ribenboim, The New Book of Prime Number Records, p. 5, Springer-Verlag 1996, 3rd edition].




The DBLP Computer Science Bibliography

Potential Interest